The volume of a right circular cone is 168π cm3 and its height is 0.12 m. Find its radius.
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Correct answer: B
Explanation
The correct answer is Option 2 i.e. √42 cm.
Volume of cone = (1/3) × π × r2 × h
Given volume = 168π cm2, height = 0.12 m = 12 cm
So, (1/3) × π × r2 × 12 = 168π
⇒ (1/3) × 12 = 4
So 4r2 = 168
→ r2 = 42
→ r = √42 cm